iOS 4.1 Phone "Speaker" mode not working

[deetsnai]

I just updated to iOS 4.1 and now people can't hear me when I'm using the phone in "Speaker" mode. I have confirmed this on two iPhone 4s with iOS 4.1. Anyone else having a problem?

 

[camarobh]

My wife's iPhone 4 has the same issue, but it started before 4.1 (while still on 4.0). I am taking it to the genius bar this weekend. The two other iPhone 4's in my family both work fine.

 

[PNutts]

I do not have that issue after updating to 4.1.